Hey.

To be eligible to take admission through NEET you need to pass Class 12th board exams through a recognised board and also score a minimum aggregate marks of 50% atleast in Physics, Chemistry and Biology together to be eligible. Other than this your marks in Class 12th wont affect your admissiom through NEET. Hence you need to score more than 50% marks in PCB. You marks and rank in NEET will be considered.

The cut off for admission in Coimbatore Medical College, Coimbatore in the previous year under the state quota for the Open category was a rank of  566 and 428 marks. Whereas for admission under the All India quota the cut off rank was a rank of 4523 and 568 marks. Hence you would require a range of marks around this for a fair chance of admission here.

Best of luck